1. Technical Field
The present invention relates to an optical filter device, and an electronic apparatus including the optical filter device.
2. Related Art
In the related art, an interference filter has been known in which reflection films which are provided to oppose each other with a predetermined gap in between, on surfaces of a pair of substrates which oppose each other. In addition, an optical filter device has been known in which such an interference filter is accommodated in a housing (for example, see JP-A-2008-70163 and JP-T-2005-510756).
An infrared type gas detector (optical filter device) disclosed in JP-A-2008-70163 includes a package (housing) which has a plate-shaped table (base substrate) and a cylindrical cap. In the housing, a periphery portion of the base substrate and a cylindrical end portion of the cap are welded or bonded to be connected to each other, and a space for accommodating a Fabry-Perot filter (interference filter) is provided between the base substrate and the cap. In this optical filter device, the interference filter is bonded to be fixed to a detection unit, and the detection unit is bonded to be fixed to an upper portion of a table of a can package.
JP-T-2005-510756 discloses an optical filter device (optical electronic device) in which a tunable optical filter (interference filter) is fixed to and accommodated in an inner portion of a package (housing). In this optical filter device, the interference filter is disposed in a vertical stack which is mounted on an upper surface of a header (base substrate) of the housing.
JP-A-2008-70163 and JP-T-2005-510756 disclose description of accommodation and fixation of the interference filter in the inner portion of the housing, however, do not disclose a specific method.
For example, in a case where the interference filter is fixed to the entire surface of the base substrate which is a fixing target, there was a concern that a reflection film is warped due to an effect from a difference in both coefficients of thermal expansion, based on temperature change. In addition, in a case of fixing the interference filter with an adhesive, there was a concern that the reflection film is warped due to an effect from contraction at the time when an adhesive is hardened, and there was a problem of degradation of optical properties.